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Nonlocality
There are historic junctures when scientific discoveries lead to theoretical paradigm shifts which in turn influence non-scientific disciplines such as philosophy or even popular cultural norms. For example, historians have linked the rise of moral relativism to popular misconceptions about Einstein's Theories of Relativity. Einstein may have been more comfortable with invariance replacing the term relativity, inferring perhaps different moral concepts, but not necessarily leading to different moral precepts among people inclined to be subjective about such matters.
Likewise many may be inclined to think that objects exist independently of our observation of them and that our observations of them have nothing to do with our behavior. But experimental results related to the study of quantum physics have challenged such notions. Nonlocality is a counterintuitive notion of quantum physics that, up to this point, has been thought of as applicable to two-particle systems. It seems as if the particles can immediately affect each other despite being separated by great distances. This conflicts with the concept that nothing travels faster than the speed of light and challenges causal concepts calling for a physical intermediary. Yet nonlocality is measurable and rooted in quantum theory.
Einstein introduced an historic thought experiment in 1935. It involved two particles moving in opposite directions and ending up at opposite ends of the galaxy. Quantumly speaking the two particles are linked, so if one particle is measured the other is instantaneously transformed by that measurement. But how would this occur over vast regions of space?1
Attempts to answer that question call to mind another paradoxical feature of science. Our understanding of physical phenomena are linked to our ability to make measurable predictions which in turn arise from mathematical descriptions of such phenomena. The classical physics of Newtonian Laws of Motion harmonize our sensual perceptions with our mathematical descriptions of objects and forces we perceive. The mathematics of quantum theories predict events that counter the intuition derived from our sensual perceptions. Perhaps this is not surprising since particles, on which quantum theory is focused, are imperceptible to our senses. We perceive them indirectly.
Charles Seife stated the paradox somewhat differently: "If we humans can't imagine a physical reality that corresponds to our equations, so what? That attitude has been called the "shut up and calculate" interpretation of quantum mechanics. But to others, our difficulties in wrapping our heads around quantum theory hint at greater truths yet to be understood."2
This should be humbling to those inclined to link their perceptions of metaphysical values to empirical results. If we cannot even conceptualize results in terms familiar to our senses, how can we be assured that not yet understood truths do not undercut basic causal assumptions about the origin of our universe and the life in it? The act of observing entails more than photons striking the retina and the subsequent biochemical and neurological events that ensue. It involves a cognitive function. Physicist F. David Peat speculates- "One of the most complex and sensitive systems in nature is the human brain and again I would suggest that a significant part of its activity takes place in a non-local fashion." The possiblity that nonlocality is an aspect of neural function, suggests a fine tuning quantum candidate for life.
Nonlocality has been associated with two particle systems but as the PhysOrg article Nonlocality of a Single Particle Demonstrated Without Objections reveals it may be possible to produce experimental evidence for the nonlocality of a single particle. There has been a debate as to whether or not an experiment can show that a single particle exhibits nonlocality. According to two physicists named Dunningham and Vedral it is not just possible but applicable to atoms and single massive particles as well as single photons. Dunningham and Vedral made changes to a proposal of another physicist named Hardy to overcome objections that a proposed experiment, attempting to combine a photon and a vacuum, would not yield an observable result. The experiment was alleged to be unfeasible because nonlocality could not be attributed to a single particle. The idea of Dunningham and Vedral is to use coherent states averaged over all phases of the particles. Quoting Dunningham, "An important feature of this work is that it shows how this experiment could be carried out without violating the number conservation superselection rule,” By avoiding this violation altogether, we show that the outcomes of this proposed experiment should be the same for both massive and massless particles."3
The author concludes by noting that credence is afforded to the idea that fields are fundamental and particles secondary; making quantum field theory a good representation of reality.
References:
1. Do Deeper Principles Underlie Quantum Uncertainty and Nonlocality?; Charles Seife; Science; July 1, 2005; Vol. 309. no. 5731, p. 98
2. Ibid.
3. Nonlocality of a Single Particle Demonstrated Without Objections; PhysOrg; http://www.physorg.com/news113824784.html